Data at NIST subscription sites:

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NIST Standard Reference
Data Program, but require an annual fee to access.
The purpose of the fee is to recover costs associated
with the development of data collections included in
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Follow the links above to find out more about the data
in these sites and their terms of usage.

The National Institute of Standards and Technology (NIST)
uses its best efforts to deliver a high quality copy of the
Database and to verify that the data contained therein have
been selected on the basis of sound scientific judgment.
However, NIST makes no warranties to that effect, and NIST
shall not be liable for any damage that may result from
errors or omissions in the Database.